JP5710707B2 - SRM detection error prevention apparatus and method - Google Patents

Description

  The present invention relates to an SRM detection error prevention apparatus and method.

  A switched reluctance motor (hereinafter, SRM) is a motor in which a switching control device is coupled, and both a stator and a rotor have a salient pole type structure.

  In particular, since the winding is wound only on the stator portion, and no form of winding or permanent magnet exists in the rotor portion, the structure is simple.

  Such a structural feature has considerable advantages in terms of manufacturing and production, and has excellent starting characteristics and a large torque like a DC motor. In addition, there is little need for maintenance, and since it has excellent characteristics in many parts such as torque per unit volume, efficiency and converter rating, the field of use tends to increase more and more.

  As a field of use of such SRM, there is a vacuum cleaner field.

  In the vacuum cleaner field, the normal operation of a suction motor for a vacuum cleaner is to generate a suction input while maintaining a constant RPM. When the amount of dust and foreign matter increases, the amount of fluid sucked decreases and the motor Since the load is reduced, the speed is increased and a constant suction force is maintained.

  Accordingly, when the RPM of the motor suddenly decreases, it is determined that the motor is damaged or the control unit is abnormal, and the motor is stopped to generate the corresponding error code.

  However, unlike a general cleaner motor, the control unit in the SRM uses AC power converted to DC voltage, and at this time, a large-capacity capacitor is used to smooth the power.

  However, since this large-capacity capacitor continuously supplies the charged current to the control unit for a certain period of time even when the power is cut off, the control unit operates for a certain period of time even when the power is cut off.

  As a result, the control unit operates in the error mode due to the motor speed reduction and corresponds to the normal SRM speed reduction due to the power shutdown, not the SRM speed decrease due to the SRM breakage or the control unit abnormality. An error code is generated continuously and the error code is stored in memory.

  As a result, when the power supply is connected later, the control unit operates again in the error mode according to the error code stored in the memory, informs the user of the error occurrence using the display unit, etc., and generates an unnecessary product repair request Or perform an error correction operation and perform an unnecessary operation (see Patent Document 1).

Korean Published Patent No. 2003-0059659

  The present invention has been derived in order to solve the above-described problems. When the fluctuation of the DC voltage is detected and the voltage falls below the voltage of the commercial power supply, it is determined that the power supply is cut off and the normal motor stop operation is performed. It is an object of the present invention to provide an SRM detection error prevention apparatus and method for preventing an operation in an error mode when a power supply is connected later.

  In order to achieve the above object, the present invention is driven by a rectifying unit that converts an AC voltage into a DC voltage and supplies the converted voltage through a capacitor, and a power source supplied from the rectifying unit. When receiving and controlling the SRM and the rotational speed of the rotor decreases below a certain value, the main control unit operating in an error mode and the fluctuation of the DC voltage supplied from the rectifying unit via the capacitor are detected. When a power shutdown is detected using a voltage detection unit to detect and a change in supply voltage detected by the voltage detection unit, the operation of the main control unit in an error mode is prevented when the power is reconnected. An error prevention unit.

  The main control unit of the device of the present invention generates and stores an error code when the rotation speed of the rotor decreases below a certain value, and the error prevention unit is detected by the voltage detection unit. When power supply interruption is detected using fluctuations in the supply voltage, the error code of the main control unit is deleted when the power is reconnected, thereby preventing the operation of the main control unit in the error mode.

  In addition, the error prevention unit of the apparatus of the present invention determines that the power supply is shut down when the rate of change of the supply voltage detected by the voltage detection unit per time is a certain value or more.

  In addition, the error prevention unit of the apparatus of the present invention determines that the power is shut off when the supply voltage detected by the voltage detection unit is a predetermined value or less.

  In addition, the voltage detection unit of the device of the present invention includes a current limiting resistor that limits a current input from the rectifying unit via a capacitor.

  In addition, the voltage detection unit of the apparatus of the present invention includes a current distributor that distributes a current input from the rectification unit via a capacitor, and the error prevention unit is any of the ones distributed by the current distributor. One DC voltage is used.

  In addition, the voltage detection unit of the device of the present invention includes a low-pass filter that removes high-frequency noise input to the voltage detection unit.

  The rectifying unit of the apparatus of the present invention receives an AC voltage from an external AC power source and converts it into a DC voltage, and supplies the DC voltage to the SRM via an inverter.

  The error prevention unit of the apparatus of the present invention transmits an SRM stop signal to the main control unit when power-off is detected, and the main control unit receives the SRM stop signal from the error prevention unit. And the driving of the SRM is stopped.

On the other hand, in the method of the present invention, (A) the voltage detection unit detects the fluctuation of the DC voltage supplied from the rectification unit via the capacitor, and (B) the error prevention unit detects by the voltage detection unit. Operation in error mode that operates when the rotation speed of the SRM rotor of the main control unit decreases to a certain value or less when the power supply is reconnected when the power supply interruption is detected using the supplied supply voltage fluctuation And a step of preventing.

  Further, according to the method of the present invention, (C) the error prevention unit transmits a stop signal of the SRM to the main control unit when the power cut-off is detected using the fluctuation of the supply voltage detected by the voltage detection unit. And (D) stopping the driving of the SRM when the main control unit receives an SRM stop signal from the error prevention unit.

  In the step (B) of the method of the present invention, the error prevention unit determines that the power supply is shut down when the rate of change of the supply voltage detected by the voltage detection unit per time is a certain value or more.

  In the step (B) of the method of the present invention, the error prevention unit determines that the power is shut down when the supply voltage detected by the voltage detection unit is equal to or less than a predetermined value.

  According to the present invention as described above, when the fluctuation of the DC voltage is detected and the voltage becomes lower than the voltage of the commercial power supply, it is determined that the power supply is cut off, and the normal motor stop operation is performed, so that the power supply is connected later. The operation in the error mode can be prevented.

  Further, according to the present invention, it is possible to prevent in advance the occurrence of a product repair request due to a detection error that occurs in a normal state.

  Furthermore, according to the present invention, it is possible to prevent in advance distrust of a user's product operation due to a detection error that occurs in a normal state.

1 is a configuration diagram of an SRM detection error preventing apparatus according to a first embodiment of the present invention; FIG. It is a block diagram of the detection error prevention apparatus of SRM by 2nd Example of this invention. 3 is a flowchart of a method for preventing an SRM detection error according to the first embodiment of the present invention;

  Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments with reference to the accompanying drawings. In this specification, it should be noted that when adding reference numerals to the components of each drawing, the same components are given the same number as much as possible even if they are shown in different drawings. I must. The terms “one side”, “other side”, “first”, “second” and the like are used to distinguish one component from another component, and the component is the term It is not limited by. Hereinafter, in describing the present invention, detailed descriptions of known techniques that may obscure the subject matter of the present invention are omitted.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram of an SRM detection error preventing apparatus according to a first embodiment of the present invention.

  Referring to FIG. 1, the SRM detection error preventing apparatus according to the first embodiment of the present invention receives an AC voltage from an external AC power source 101, converts it into a DC voltage, and outputs the DC voltage. An inverter 103 that converts a DC voltage from one rectifying unit 102 into an AC voltage and supplies it to the SRM 107, an inverter driving unit 104 for driving the inverter 103, and a rotor that detects the rotational speed of the rotor of the SRM 107 The detection unit 105, the main control unit 106 that receives the detection signal from the rotor detection unit 105 and reflects it in the control of the inverter driving unit 104, and the AC voltage from the AC power source 101 is changed to an AC voltage of a different magnitude. A transformer 108 for conversion, a second rectifier 109 that receives the secondary side voltage of the transformer 108, converts it into a DC voltage, and outputs it; and a second rectifier 10 The voltage detection unit 110 that detects the fluctuation of the power supply voltage by detecting the output voltage from the power supply, and the power cutoff is detected using the voltage detected by the voltage detection unit 110, and the main control unit 106 is stopped accordingly. And an error prevention unit 112 for preventing an operation in the error mode when the power supply is connected after the operation.

  Here, the second rectifier 109 supplies a DC voltage to the main controller 106, and at this time, the DC voltage is supplied via the capacitor C2.

  Here, the voltage detection unit 110 uses the current limiting resistor R1 for preventing the occurrence of overcurrent due to the output voltage from the second rectification unit 109, and the output voltage from the second rectification unit 109 as a specific voltage. A plurality of voltage distribution resistors R2 and R3 for setting less than the value, and a capacitor C3 for removing high frequency noise mixed in the voltage distributed and supplied by the plurality of voltage distribution resistors R2 and R3 And a low-pass filter 111 made of

  Reference numeral C1 in FIG. 1 is a capacitor for removing a surge component mixed in the induced voltage induced on the secondary side of the transformer 108, and C2 is from the second rectifier 109. It is a smoothing capacitor for removing the pulsating component of the output DC voltage.

  In the first embodiment of the SRM detection error preventing apparatus according to the present invention having such a configuration, the first rectifying unit 102 converts the AC voltage applied from the AC power source 101 into a DC voltage, and outputs the DC voltage. Receives the DC voltage output from the first rectifier 102, converts it to an AC voltage suitable for driving the SRM 107, and outputs the AC voltage.

  Thus, when the SRM 107 is driven, the rotor detection unit 105 detects the rotation speed of the rotor and transmits it to the main control unit 106, and the main control unit 106 receives the detection signal from the rotor detection unit 105. The control signal is compared with the set reference signal and a corresponding control command is transmitted to the inverter driving unit 104.

  Then, the inverter driving unit 104 controls the voltage applied to the SRM 107 according to the control command, and as a result, the rotational speed of the SRM 107 is controlled.

  The transformer 108 converts the voltage from the AC power source 101 into an AC voltage having a different magnitude depending on the ratio of the number of coil turns on the primary side and the secondary side. Receives side voltage, converts to DC voltage and outputs.

  In the series of processes as described above, when the voltage of the AC power supply 101 from the outside is changed, the output voltage of the first rectifying unit 102 is also changed.

  When the voltage of the AC power supply 101 is thus changed, the output voltage of the first rectifying unit 102 is also changed, and the rotation speed of the SRM 107 is changed.

  When the voltage of the AC power supply 101 from the outside is changed, the voltage induced on the secondary side of the transformer 108 and the output voltage of the second rectifying unit 109 are also changed.

  At this time, the DC voltage output from the second rectifier 109 is distributed at a predetermined ratio by the resistors R2 and R3 of the voltage detector 110, and the fluctuation of the DC voltage is reflected.

  Then, the error prevention unit 112 receives a change in voltage reflected by the resistor R3 among the distributed voltages, and determines a change in the DC power supply.

  On the other hand, when the voltage of the AC power supply 101 from the outside is cut off, the output voltage of the first rectifying unit 102 is also cut off.

  Thus, when the voltage of AC power supply 101 is interrupted, the output voltage of first rectifier 102 is also interrupted, and the rotational speed of SRM 107 is reduced.

  However, when the power supply is cut off, the main control unit 106 operates for a certain period of time to continue supplying power to the main control unit 106 even if the current charged by the large-capacitance capacitor C2 removes the power supply. .

  As a result, when the power supply is suddenly shut down, the speed of the SRM 107 decreases rapidly, but the main control unit 106 continues to operate and operates in an error mode due to the decrease in the speed of the SRM output from the rotor detection unit 105. Then, the error code is generated continuously, and the generated error code is stored in the memory.

  When the error code is generated by the main control unit 106 in this way and the generated error code is stored in the memory, the main control unit 106 determines the error by the error code stored in the memory when the power is connected later. It is determined that the error has occurred, and an alarm unit (not shown) or the like is used to notify the user of the occurrence of an error or to perform an error correction operation.

  In this way, when the main control unit 106 operates in the error mode according to the error code stored in the memory and informs the user of the occurrence of the error using an alarm unit or the like, an unnecessary product repair request is generated or the error correction is performed by itself. The operation is performed to perform an unnecessary operation.

  Therefore, it is necessary to prevent this. In the present invention, therefore, the voltage detection unit 110 detects a voltage fluctuation, the error prevention unit 112 recognizes the voltage interruption due to the voltage fluctuation, and prevents the main control unit 106 from operating in an error mode when the power is connected. Like that.

  More specifically, when the voltage of the AC power supply 101 from the outside is cut off, the voltage induced on the secondary side of the transformer 108 and the output voltage of the second rectifying unit 109 are also cut off.

  However, although the power is continuously supplied to the main control unit 106 by the current charged in the large-capacitance capacitor C2, the supplied power gradually decreases.

  At this time, the DC power supplied to the main control unit 106 by the large-capacitance capacitor C2 is distributed at a predetermined ratio by the resistors R2 and R3 of the voltage detection unit 110, and the fluctuation of the DC voltage is reflected.

  Then, the error prevention unit 112 receives the fluctuation of the voltage reflected by the resistor R3 among the distributed voltages, and determines whether or not the DC power supply is shut off.

  That is, the error prevention unit 112 obtains the rate of change (gradient) of the detected voltage per time, and determines that the power is shut off when the voltage is below a certain value.

  Of course, the error prevention unit 112 can also determine that the power supply is shut down when the detected voltage falls below a certain value.

  When it is determined that the power is shut down in this way, the error prevention unit 112 transmits an error code deletion signal due to a decrease in the SRM speed to the main control unit 106.

  Then, the main control unit 106 deletes the error code due to the SRM speed reduction stored in the memory.

  As described above, when the error code due to the decrease in the SRM speed stored in the memory is deleted by the main control unit 106, the operation in the error mode due to the error code can be prevented when the power is reconnected after the power is turned off. .

  As a result, the occurrence of a product repair request due to a detection error that occurs in a normal state can be prevented in advance.

  Further, according to the present invention, it is possible to prevent in advance distrust of a user's product operation due to a detection error that occurs in a normal state.

  On the other hand, the error prevention unit 112 transmits an SRM stop signal to the main control unit 106 when a power interruption is detected, and the main control unit 106 receives an SRM stop signal from the error prevention unit 112. The driving of the SRM can be stopped.

  In this way, the main control unit 106 can detect an error and stop the operation of the SRM 107 faster than the time for stopping the SRM.

  FIG. 2 is a block diagram of an SRM detection error preventing apparatus according to a second embodiment of the present invention.

  Referring to FIG. 2, the SRM detection error preventing apparatus according to the second embodiment of the present invention receives an AC voltage from an external AC power supply 201, converts it into a DC voltage, and outputs the DC voltage. An inverter 203 that converts the DC voltage from the converter into an AC voltage and supplies the AC voltage to the SRM 207, an inverter drive unit 204 for driving the inverter 203, and a rotor detection unit 205 that detects the rotational speed of the rotor of the SRM 207 The main control unit 206 that receives the detection signal from the rotor detection unit 205 and reflects it in the control of the inverter driving unit 204 and the output voltage from the rectification unit 202 are detected to detect the fluctuation of the power supply voltage. The power detection is detected by using the voltage detection unit 208 and the voltage detected by the voltage detection unit 208, and the main control unit 206 Including an error prevention part 210 so as to prevent the operation of the re-connection time error mode source, a.

  Here, the rectifying unit 202 not only supplies a DC voltage to the inverter 203 but also supplies a DC voltage to the main control unit 206, and at this time, the DC voltage is supplied via the capacitor C1.

  The voltage detection unit 208 includes a current limiting resistor R1 for limiting the current supplied from the capacitor C2, and a plurality of voltage distribution resistors R2, R3 for setting the supply voltage below a specific voltage value. And a low-pass filter 209 for removing high-frequency noise mixed in the voltage distributed by the plurality of voltage distribution resistors R2 and R3. The low-pass filter 209 is composed of a capacitor C2.

  Next, the error prevention unit 210 detects a power cutoff using a DC power source that has passed through the low-pass filter 209, and transmits an error code deletion signal to the main control unit 206 when a power cutoff is detected. To prevent operation in error mode when reconnecting.

  Reference numeral C <b> 1 in FIG. 2 is a smoothing capacitor for removing a pulsating component mixed in the DC voltage supplied by the rectifying unit 202.

  The operation of the SRM detection error preventing apparatus according to the second embodiment having the above-described configuration will be described as follows.

  The rectifier 202 converts the AC voltage applied from the AC power supply 201 into a DC voltage and outputs the DC voltage. The inverter 203 receives the DC voltage output from the rectifier 202 and converts it into an AC voltage suitable for driving the SRM 207. Convert and output.

  Thus, when the SRM 207 is driven, the rotor detection unit 205 detects the rotation speed of the rotor and transmits it to the main control unit 206, and the main control unit 206 receives the detection signal from the rotor detection unit 205. Then, the control command corresponding to the reference signal is transmitted to the inverter drive unit 204.

  Then, inverter drive unit 204 controls the voltage applied to SRM 207 in accordance with the control command, and as a result, the rotational speed of SRM 207 is controlled.

  The rectifying unit 202 not only supplies a DC voltage to the inverter 203 but also supplies a DC voltage to the main control unit 206.

  At this time, the rectifying unit 202 supplies a DC voltage to the main control unit 206 via the capacitor C1, and the capacitor C1 supplies a smoothed power supply.

  Even if the current charged by the capacitor C1 removes the power supply, the main control unit 206 continues to supply power to the main control unit 206, so that the main control unit 206 operates for a certain period of time.

  As a result, when the power supply is suddenly shut down, the speed of the SRM 207 decreases rapidly, but the main control unit 206 continues to operate and operates in an error mode due to the decrease in the speed of the SRM to generate an error code continuously. The error code that occurred is stored in memory.

  When the error code is generated by the main control unit 206 and the generated error code is stored in the memory, the main control unit 206 uses an alarm unit (not shown) or the like when the power is connected later. Inform the user of the error.

  However, this is not an abnormality of the SRM 207 but a decrease in the speed of the SRM 207 due to power interruption. In order to prevent this, the present invention includes the voltage detection unit 208 and the error prevention unit 210.

  The voltage detector 208 distributes the DC voltage supplied from the capacitor C1 at a predetermined ratio using resistors R2 and R3.

  In addition, the error prevention unit 210 receives a voltage drop due to the resistor R3 from among the distributed voltages, obtains a rate of change (gradient) of the detected voltage per time, and determines that the power is shut down when the voltage falls below a certain value. To do.

  Of course, the error prevention unit 210 receives the voltage drop due to the resistor R3 among the distributed voltages, and can determine that the power supply is shut down when the voltage falls below a certain value.

  When it is determined that the power is shut down in this way, the error prevention unit 210 transmits to the main control unit 206 an error code deletion signal due to the SRM speed reduction.

  Then, the main control unit 206 deletes the error code due to the SRM speed error stored in the memory.

  As described above, when the error code due to the decrease in the SRM speed stored in the memory is deleted by the main control unit 206, the operation in the error mode due to the error code can be prevented when the power is reconnected after the power is turned off. .

  As a result, the occurrence of a product repair request due to a detection error that occurs in a normal state can be prevented in advance.

  Further, according to the present invention, it is possible to prevent in advance distrust of a user's product operation due to a detection error that occurs in a normal state.

  On the other hand, the error prevention unit 210 transmits an SRM stop signal to the main control unit 206 when power-off is detected, and the main control unit 206 receives an SRM stop signal from the error prevention unit 210. The driving of the SRM can be stopped.

  In this way, the main control unit 206 can detect an error and stop the operation of the SRM 107 faster than the time for stopping the SRM.

  FIG. 3 is a flowchart of an SRM detection error preventing method according to the first embodiment of the present invention.

  Referring to FIG. 3, the SRM detection error preventing method according to the first embodiment of the present invention is performed when the DC power converted from the AC power by the rectifier is supplied to the main controller via the large capacity capacitor. The voltage variation is detected by the voltage detector (S100).

  At this time, when detecting the fluctuation of the supply voltage, the voltage detection unit detects the current while limiting the current using a current limiting resistor, thereby preventing damage to the internal circuit.

  In addition, when detecting the fluctuation of the supply voltage, the voltage detection unit distributes the voltage using the voltage distributor, and detects the fluctuation of the supply voltage using the distributed voltage.

  The voltage detection unit filters the supply voltage using a low-pass filter, removes high frequency noise, and detects fluctuations in the supply voltage.

  The error prevention unit determines whether or not the power is shut off based on the voltage detected by the voltage detection unit (S110).

  At this time, the error prevention unit measures the amount of change in voltage per hour, and determines that the power is shut down when the rate of change (gradient) per hour is equal to or greater than a certain value.

  Alternatively, the error prevention unit can determine that the power is cut off when the voltage becomes a certain value or less.

  Next, when it is determined that the power is shut off (S120), the error prevention unit transmits an error code deletion signal to the main control unit, and the main control unit deletes the error code, thereby supplying power to the main control unit. When reconnecting, the main control unit does not operate in the error mode (S130).

  On the other hand, if it is determined that the power is not shut down, the error prevention unit terminates without performing any operation. As a result, the main control unit generates a corresponding error code when the SRM speed falls below a certain value due to instability of the reference power supply, and notifies the user of the error or performs processing for the error according to the corresponding error code. The error is controlled, and the result is stored in the memory (S140).

  On the other hand, the error prevention unit transmits an SRM stop signal to the main control unit when the power interruption is detected, and the main control unit drives the SRM when the SRM stop signal is input from the error prevention unit. It can be stopped (S150).

  In this way, the operation of the SRM can be stopped faster than the time for the main control unit to detect an error and stop it.

  According to the present invention as described above, when the fluctuation of the DC voltage is detected and the voltage becomes lower than the voltage of the commercial power supply, it is determined that the power supply is cut off, and the normal motor stop operation is performed, so that the power supply is connected later. The operation in the error mode can be prevented.

  Further, according to the present invention, it is possible to prevent in advance the occurrence of a product repair request due to a detection error that occurs in a normal state.

  Furthermore, according to the present invention, it is possible to prevent in advance distrust of a user's product operation due to a detection error that occurs in a normal state.

  As described above, the present invention has been described in detail based on the specific embodiments. However, the present invention is only for explaining the present invention, and the present invention is not limited thereto. It will be apparent to those skilled in the art that modifications and improvements within the technical idea of the present invention are possible.

  All simple variations and modifications of the present invention belong to the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

  The present invention is applicable to an SRM detection error prevention apparatus and method.

101, 201 AC power supply 102 First rectifier 109 Second rectifier 202 Rectifier 103, 203 Inverter 104, 204 Inverter driver 105, 205 Rotor detector 106, 206 Main controller 107, 207 SRM
108 Transformer 110, 208 Voltage detection unit 111 209 Low-pass filter 112, 210 Error prevention unit

Claims (13)

A rectifying unit that converts an alternating voltage into a direct voltage and supplies it through a capacitor;
The main control that is driven by the power supplied from the rectifying unit, receives the rotational speed of the rotor of the SRM, controls the SRM, and operates in an error mode when the rotational speed of the rotor decreases below a certain value. And
A voltage detection unit that detects a change in a DC voltage supplied from the rectification unit via the capacitor;
An error prevention unit for preventing an operation in an error mode of the main control unit when reconnecting a power source when a power supply interruption is detected using a fluctuation in supply voltage detected by the voltage detection unit; SRM detection error prevention device including: The main control unit generates and stores an error code when the rotational speed of the rotor decreases below a certain value,
When the power prevention is detected using the fluctuation of the supply voltage detected by the voltage detection unit, the error prevention unit deletes the error code of the main control unit when the power is reconnected, thereby removing the main control unit. The SRM detection error preventing apparatus according to claim 1, wherein the controller prevents an operation in an error mode.   2. The SRM detection error preventing apparatus according to claim 1, wherein the error prevention unit determines that the power is shut down when a rate of change of the supply voltage detected by the voltage detection unit per unit time is a predetermined value or more.   2. The SRM detection error prevention apparatus according to claim 1, wherein the error prevention unit determines that the power is shut off when the supply voltage detected by the voltage detection unit is equal to or less than a predetermined value.   The SRM detection error preventing apparatus according to claim 1, wherein the voltage detection unit includes a current limiting resistor that limits a current input from the rectifying unit via a capacitor. The voltage detector includes a current distributor that distributes a current input from the rectifier through a capacitor,
The SRM detection error prevention apparatus according to claim 1, wherein the error prevention unit uses any one DC voltage distributed by the current distributor.   The SRM detection error prevention apparatus according to claim 1, wherein the voltage detection unit includes a low-pass filter that removes high-frequency noise input to the voltage detection unit.   2. The SRM detection error preventing apparatus according to claim 1, wherein the rectifier unit receives an AC voltage from an external AC power source, converts the AC voltage into a DC voltage, and supplies the DC voltage to the SRM via an inverter. The error prevention unit transmits an SRM stop signal to the main control unit when power-off is detected,
The SRM detection error prevention apparatus according to claim 1, wherein the main control unit stops driving of the SRM when an SRM stop signal is input from the error prevention unit. (A) the voltage detection unit detects a change in the DC voltage supplied from the rectification unit via the capacitor;
(B) When the error prevention unit detects that the power supply is cut off using the fluctuation of the supply voltage detected by the voltage detection unit , the rotation speed of the SRM rotor of the main control unit is constant when the power supply is reconnected. And a method of preventing an operation in an error mode that operates when the value decreases below a value . (C) the error prevention unit transmits a stop signal of the SRM to the main control unit when the power cutoff is detected using the fluctuation of the supply voltage detected by the voltage detection unit;
The method according to claim 10, further comprising: (D) stopping the driving of the SRM when the main control unit receives an SRM stop signal from the error prevention unit.   11. The SRM detection according to claim 10, wherein, in the step (B), the error prevention unit determines that the power is shut down when a rate of change of the supply voltage detected by the voltage detection unit per time is a predetermined value or more. Error prevention method.   The method of claim 10, wherein the error prevention unit determines that the power is shut down when the supply voltage detected by the voltage detection unit is equal to or lower than a predetermined value.

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